The present invention is generally related to the field of mass storage devices including a hard disk drive (HDD) controllers, and more particularly to detecting excess current on servo driver IC""s.
Servo driver integrated circuits (IC""s) are typically used in mass storage devices including hard disk drive (HDD) control circuits for controlling a spindle motor. Occasionally, excess current conditions to the spindle motor can cause damage to the servo driver, and may also produce excess heat and cause a fire hazard. Conserving die space and minimizing power consumption is a key design criteria for these servo driver IC""s.
There is desired an improved servo driver IC capable of detecting excess current of servo drive IC that can facilitate reducing the excess IC current. There is also desired a small protection circuit that can eliminate the excess current condition.
The present invention achieves technical advantages by detecting excess current on any IC including a servo driver IC and preventing the disruptive damage which can be caused by the excess current. Typically, an isolation (Iso) FET is part of the servo driver IC. A detection circuitry having only a small silicon area is added whereby the detection circuit is independent of the Iso FET current path, being in parallel rather than in series. The detection circuitry also allows production tests on much smaller current thresholds.